1. Field of the Invention
The present invention relates generally to audio processing, and more particularly to audio signal analysis.
2. Description of Related Art
Audio communication networks often have bandwidth limitations that affect the quality of the audio transmitted over the network. For example, telephone channel networks limit the bandwidth received by the receiver to 300 Hz to 3500 Hz. As a result, speech transmitted using only this limited bandwidth sounds thin and dull due to the lack of low and high frequency content in the audio signal.
Previous systems approached the issue in different ways. Some systems attempt to improve audio quality in a narrow bandwidth system by dividing the received signal into an envelope and an excitation portion. The system then analyzed and attempted to extend the bandwidth of both the envelope and excitation signals independently. This system requires a lot of resources and introduces latency in the processing.
Some previous systems attempt to remedy a narrow band audio signal by determining a mapping of the signal frequency components and reconstructing missing frequencies using an algorithm based on the mapped signal frequency components. This system also is not practical for use with audio applications due to introduced latency effects.
Therefore, there is a need for systems and methods to be able to quickly and efficiently improve the audio quality over bandwidth limited networks.